HOME HELP CONTACT US SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:
Sign In to gain access to subscriptions and/or personal tools.

This Article Full Text Full Text (PDF) All Versions of this Article: 32/5/1263    most recent 0363546503262199v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Request Reprints Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Song, H. Articles by Nakajima, H. Search for Related Content PubMed PubMed Citation Articles by Song, H. Articles by Nakajima, H. Related Collections Ankle Muscle Animal studies

Effect of Increased Excursion of the Ankle on the Severity of Acute Eccentric Contraction-Induced Strain Injury in the Gastrocnemius

An In Vivo Rat Study

From the Nippon Sport Science University, Tokyo, Japan

^* Address correspondence to Koichi Nakazato, Nippon Sport Science University, 7-1-1, Fukasawa, Setagaya-ku, Tokyo, Japan 158-8508 (e-mail: nakazato{at}nittai.ac.jp).

Background: Although muscle strain injury models are frequently employed, highly invasive procedures, including surgical intervention, are typically used to produce these models. In this study, a minimally invasive model of acute strain injury was produced with a single eccentric contraction.

Hypothesis: The authors tested whether the severity of strain injury in the in vivo gastrocnemius depends on the excursion of the ankle.

Study Design: Controlled laboratory study.

Methods: Animals were randomly assigned to 2 groups: a small range of motion group (90°–105°, n = 10) and a large range of motion group (90°–125°, n = 10). Tetanically activated gastrocnemius muscles with percutaneous electrical stimulation were simultaneously elongated by forced dorsiflexion of the ankle joint.

Results: Isometric tetanic force of the large range of motion group was significantly lower than the pretreatment control 1, 2, and 3 days after treatment. Such reduction was not observed in the small range of motion group. Apparent pathologic damage was observed in the large range of motion group throughout the study period of 10 days.

Conclusions: A larger range of motion causes more damage in eccentric contraction by using the in vivo model.

Clinical Relevance: This in vivo model is useful to elucidate mechanisms of prevention and recovery of strain injury.

Key Words: muscle • strain • eccentric • force • deficit • gastrocnemius

This article has been cited by other articles:

				T. A. Butterfield and W. Herzog Effect of altering starting length and activation timing of muscle on fiber strain and muscle damage J Appl Physiol, May 1, 2006; 100(5): 1489 - 1498. [Abstract] [Full Text] [PDF]

				N. N. Mahieu, E. Witvrouw, V. Stevens, D. Van Tiggelen, and P. Roget Intrinsic Risk Factors for the Development of Achilles Tendon Overuse Injury: A Prospective Study Am. J. Sports Med., February 1, 2006; 34(2): 226 - 235. [Abstract] [Full Text] [PDF]